MX and DNS setup a cox.net appears to be good enough that I do not see it as a
culprit.
I would suggest looking at your resolvers and their configurations.
Perhaps too many recursive queries (?). See quota reached in your syslog?
HTH -- Chris
--- Will <westes-usc at noemail.nospam> wrote:
> I have several well-known hosts that are failing A record lookups on DNS and
> I need help debugging this.
>> We have the ISC Bind 9.3.0 set up on a box with a sendmail mail server, just
> to speed up the MX lookups on that box. I go to the nslookup command line,
> and type something like the following:
>> type=mx
> cox.net
>> and what I get back is a timeout that lasts two seconds and then no
> response.
>> I start a sniffer, and record while performing the above. There is no
> question that the name server is issuing the query, and that the remote DNS
> responds with the nameserver (NS) records for cox.net.
>> At this point, the sniffer trace shows that there is a timeout on simple
> Address (A) record lookups to all nameservers for cox.net.
>> I confirm that result from the command line by simple nslookup to ns.cox.net
> (for example) and this does time out.
>> I jump over to a UNIX box outside our network and try the same queries, and
> they all immediately work.
>> What are some possible causes for this? Could cox.net be blacklisting
> many Internet hosts on their nameservers?
>> --
> Will
>>>>